William James

Interactive processors for design use of large program packages

Civil engineering design methodology is changing as a result of emerging computer hardware and software. Highspeed, interactive, user-friendly systems are more common, whereas formerly batch submission of batch-oriented programs was the only common method. However, a variety of large, complex program packages are still widely used for urban drainage design problems. These packages are usually executed on mainframes with a large memory capacity and high computing speeds; users need a good working knowledge of FORTRAN input requirements and mainframe job control language, especially when the packages are used in a multi-program, multiprocessor environment. Furthermore, long learning times are associated with the implementation and execution of complex packages on batch-oriented mainframes at remote sites.This paper discusses the design of an interactive package of pre- and post-processors to facilitate input data preparation, job execution, output interpretation, and job resubmission in a multi-program, mul...

Power spectral analysis of a forcemain failure caused by waterhammer

The 14 in. (0.36 m) forcemain followed an overall convex pipeline profile for 4000 ft (1200 m) and would be subject to negative surge problems associated with pump shutdown. The forcemain couplings failed three times near the pumphouse and the failure was thought to be related to waterhammer effects. The sequence of breakages is reviewed. A series of pressure recordings were then made over 14 days on the repaired forcemain, leading up to and including the final failure. These pressure recordings were digitized and subjected to power spectral analysis. The power spectra pointed out several significant events that were not evident from the pressure record alone.These included the fact that the original breakdown in the forcemain occurred several days prior to its ultimate failure and discovery on the surface. It was also determined that the break in the system was due to the apparent merging of the primary waterhammer wave with an existing but gradually changing lower frequency wave. This second wave was as...